Field of Invention
The present invention relates to an intelligent transportation field, and more particularly to an online traffic volume monitoring system based on a phase-sensitive optical time domain reflectometry and a monitoring method thereof.
Description of Related Arts
With the improvement of people's living standards, private vehicles have increased dramatically. Traffic jams occurring on roads in each city or town during rush hours and holidays bring great inconvenience in people's daily life. As a result, it is an urgent and important issue to monitor the vehicle flow and the traffic situation on line in cities to guide traffic orderly, avoid congestion, and realize an intelligent traffic control. The online vehicle flow monitoring is one of the key technologies for intelligent traffic management, which provides real-time and accurate information for the transportation administrations and the vehicle owners by detecting the vehicle flow at different road segments and intersections, and solves a series of problems that congestion brings. The conventional vehicle flow detection technology is mainly based on video surveillance (CN 1024199906 A, 2012), which detects and counts the vehicle targets in continuous video stream through the image acquisition and analysis. However, the video surveillance technology depends highly on the light condition of the background. The image quality of the video deteriorates significantly at night when it is lacking of light, and the accuracy of recognition declines. The infrared detection technology depends much less on light condition. However, in order to enhance the sensitivity, the output power of the infrared detection system needs to be increased by sacrificing the long-term stability (CN 1967623 A, 2006). The monitoring technology based on the Internet of Things by using the electronic sensor network (CN 103578280 A, 2014) has some advantages of responding in real time with a simple detecting method, but still has difficulties in battery replacement and long-term maintenance, especially the difficulty that hundreds of, even thousands of, sensor nodes are needed when monitoring a wide area or a long road.